State of Charge (2012)

The report evaluates regional electricity grids across the United States based on the global warming emissions produced from electricity generation, and then compares the emissions generated by charging an EV with those produced by gasoline-powered vehicles.

UPDATE September 2014: Thanks to efficiency improvements, electric vehicles continue to become cleaner. Read more here.

UPDATE June 2012: Report and infographic updated with new 2009 power plant data.

Electric Vehicles and Global Warming Emissions

Electric vehicles (EVs) burn no gasoline and have no tailpipe emissions, but producing the electricity used to charge them does generate global warming emissions. The amount of these emissions, however, varies significantly based on the mix of energy sources used to power a region's electricity grid.

For example, coal-fired power plants produce nearly twice the global warming emissions of natural gas-fired power plants, while renewable sources like wind and solar power produce virtually no emissions at all.

The UCS report, State of Charge: Electric Vehicles' Global Warming Emissions and Fuel-Cost Savings Across the United States, compares the global warming emissions from EVs with those from gasoline-powered vehicles and finds that:

Nationwide, EVs charged from the electricity grid produce lower global warming emissions than the average compact gasoline-powered vehicle (with a fuel economy of 27 miles per gallon)—even when the electricity is produced primarily from coal in regions with the “dirtiest” electricity grids.

In regions with the “cleanest” electricity grids, EVs produce lower global warming emissions than even the most fuel-efficient hybrids.